Bullseye Power’s Map Width Enhancement Groove: Next-Level Surge Control and Tunable Powerbands

Bullseye Power’s Map Width Enhancement Groove: Next-Level Surge Control and Tunable Powerbands

Bullseye Power has long been recognized for innovating cutting-edge turbocharger technology, and the Map Width Enhancement Groove (MWEG) is a testament to this legacy. If you’re looking to maximize the efficiency and power delivery of your engine while preventing compressor surge, understanding Bullseye’s patented tunable MWEG is essential. Here’s what makes this technology stand out for the new era of high-performance turbocharging.

What Is a Map Width Enhancement Groove?

A Map Width Enhancement Groove is an engineered pathway that runs between the front of a compressor cover and a slot deep inside the bore, well behind the leading edge of the compressor wheel. Its main purpose? Preventing compressor surge—a common challenge that can hurt performance and reliability. Compressor surge occurs when the compressor produces more pressure than the engine can consume, causing flow reversal and instability.

The MWEG allows for a bypass route for some compressed air, stabilizing the airflow and keeping the system in an efficient operating range—even as conditions change.

The Tunable Advantage: Adjustable Power, Real Results

What makes Bullseye’s system truly unique is the patented tunable race cover. With this design:

  • Groove width can be adjusted to match your engine's specific Volumetric Efficiency (VE).

  • It's not about adding “cheater” power, but about moving power where it’s most useful. For example, you might want more low-end grunt for a heavy truck, or to push power higher up the band for better traction at the track.

  • Many grooves come standard between .200 and .250 inches (200-250 thousandths), but fine-tuning is possible for unique builds.

  • Third-party testing with a 76mm turbo has shown up to 45–50hp can be shifted from the front to the top of the powerband. This is ideal for applications where you want to soften bottom-end punch and build more power up top, or vice versa.

How Does Tunability Work?

The compressor cover features a threaded inlet bell. Each turn of the bell—closed (clockwise) or open (counterclockwise)—changes the groove width by about 1/16th of an inch. Up to 6 full turns are possible, letting you tailor the turbo’s response for your specific engine and application.

Tuning Steps:

  • Start with the groove closed.

  • Make runs and record performance.

  • Open in 1 or 2 full turn increments and continue testing until you find your optimal setup.

  • Remember: This process can drastically affect both horsepower and torque delivery across the RPM range.

Who Benefits Most?

  • Racers: Want to fine-tune power delivery for varying track conditions and consistently stay out of surge.

  • Street enthusiasts: Can tune for better driveability—smoother power where you want it, and a more reliable, efficient setup.

  • Truck/Heavy-duty users: Shift power up or down the band for better traction or towing power based on the engine’s needs.

The Map Width Enhancement Groove from Bullseye Power isn't just about preventing surge—it's about unlocking the perfect powerband for your unique vehicle and driving style. Whether you’re chasing championships, building a street monster, or optimizing a workhorse, Bullseye’s patented tunable compressor covers help you fine-tune performance like never before, making every application perform at its best.

Back to blog